Ignition system



W. 0. KENNINGTON- IGNITION SYS TEM. APPUCATION FILED SEPLZI, ms.

1,347,5 1 1 Patent/ed July 27, 1920.

UNITED STATES PATENT OFF-ICE.

WILLIAM 0. KENNINGTON, OF LONDON, ENGLAND, ASSIGNOR TO THE BEMY ELECTRIC CQMPANY, ACOBPOBATION OF INDIANA.

IGNITION SYSTEM.

Specification of Letters l atent.

Patented July 27, 1920.

To all whom it may concern:

Be it known that I, WILLIAM O. KEN- NING'roN, a subject of the King of Great Britain, residing at 14 Panton street, London, England, have invented certain new and useful Improvements in Ignition Systoms, of which-the following is a full, clear, and exact description. V

This invention relates to ignition systems forexplosion engines and has among its objects to provide means for preventing ignition upon the reverse rotation of the engine.

As a preferred means of carrying out this invention, I provide two breaker arms for the timing device, these breaker arms being arranged in series in the primary circuit. These breaker arms are operated in quick succession but the device is so arranged that in the normal forward rotation of the engine the current through the primary is broken in such manner as to produce a spark, whereaslupon reverse rotation of the engine the breaking of the primary circuit is in a manner which will not produce sufficient spark for ignition purposes.

Further objects of the invention will be apparent from the ensuing description with reference to the accompan ing drawing.

The figure of said drawing is a diagrammatic view of an ignition system containing the invention referred to.

The battery 10 is a source of current for the primary coil 11, in cooperation with which is the secondary 12, connected by lead wire 13 to the rotor 14 of the distributer. This rotor distributes the high tension current tothe various distributor posts 15, when rotating in the direction of the arrow, so as to distribute the sparking impulses to the various cylinders in the well known manner. The rotor 14 is shown diagrammatically as mounted to rotate upon a shaft 16,and this same shaft is connected, as also "shown diagrammatically, to rotate two timer cams, namely a main timer cam 17 and an auxiliary timer cam 18.

The cam 17 operates upon a breaker arm 19 and the cam 18 operates upon a breaker arm 20. These breaker arms are held normally toward the cams by springs 21. and 22 res ectivel t the eiid of the breaker arm 19 is a contact 23, cooperating with the stationary con- :tact 24. And similarly there is a contact 25 on the end of, the breaker arm 20 cooperatingwith a stationary contact 26.

The lead wire 27 from the primary coil 11 is connected to the contact 241 And from this point a'condenser 28 is shunted around the contacts 23, 24 and the breaker arm 19.

A lead wire 29 leads from the breaker arm 19 to the breaker arm 20, and a lead wire 30 connects the contact 26 WltlLtllB battery 1U, so that these breaker arms are then in series with the battery and the primary coil.

The general construction of these timer cams and breaker arms and their arrangement in the primary ignition circuits is well known in the art, but the feature of the present invention comprises having two breaker arms in series in this primary circuit, with the respective cams slightly displaced as to rotary effect so that one breaker arm is ope'rated slightly before the other in the normal rotation of the engine. 1

For example, it will be seen in the diagrammatic showing of Fig. 1, that the timer cam 17, rotating in the direction of the arrow, has just operated upon the breaker arm. 19 to break the primary circuit at the contacts 23, 24. But at this time, the auxiliary timer cam 18, also rotating in the direction of the arrow (and being connected to rotate with the other timer cam) has not yet moved far enough to break the primary circuit at the contacts 25', 26.

However, the breaking of the main circuit through the primary coil 11 at the contacts 23, 24, through the assistance of the condenser 28 is arranged to give the r 'eg uisite sparking impulse through the rfi'il" um of the secondary'coil 12.

The, continued rotation of the two timer cams in the direction of the arrow causes the circuit to be broken at the auxiliary eontacts 25, 26, and then both sets of contacts are again closed so as to remake the primary circuit in the next succeeding operation. In this operation, the opening of the circuit at the contacts 25, 26 has no effect because the circuit has already been broken through the main contacts 23, 24.

Now, however, if the engine should rotate reversely, it will be seen that in such case the auxiliary cam 18 would be the first to break the primary circuit, namely at the contacts 25, 26. And the breaking at the main contacts 23, 24 would not take place until just immediately afterward, but with out any sparking effect because the circuit had already been broken at the contacts 25, 26.

It will be noted that there is no condenser shown across-these auxiliary contacts 25, 26 such as is the case with the main contacts 23, 24. A further feature of the invention is that these auxiliary contacts 25,

.26 are made of nickel and operate, when no condenser is present, to cause arcing to occur between them when separated to effect the discharge of the ignition coil. The character of the are or flame produced between these nickel contacts is such as to produce a sluggish breaking of the primary circuit and a relatively slow discharge of the energy of the ignition coil. The rate of discharge of the coil in this manner is such that the sparking impulse induced in the sec ondary is so weak that no spark will jump at the engine spark plug.

It is supposed that the are or flame which occurs between the nickel contacts at the time of separation upon reversal of the engine, actsv as a current conducting medium having such a resistance as gradually to cause a reduction of ampere-turns in the ignition coil, and thus prevent a sudden discharge of the energy of the coil.

Material other than nickel may be used to construct the auxiliary contacts provided the flame or are produced between them possesses the properties which have been mentioned in connection with the nickel contacts.

Thus it results that these contacts may be made of cheaper metal rather than the more expensive material such as platinum or tungsten which is customarily used for the main make and break points of the primary circuit.

I have further found it to be of some advantage in certain cases to vary the size of the contacts 25, 26 according to different metals used.

While the forms of mechanism herein shown and described constitute preferred forms of embodiments of the invention, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

1. In an ignition system, a non-back-firing device comprising a primary coil with a source of current therefor, and a secondary coil with connections for producing spark ing impulses; of a main make and break point, and an auxiliary make and break point, both in series in said primary circuit; means for operating said make and break points in quick succession, the main make and break point being operated first in the normal rotation of the engine and last in the reverse rotation, with a condenser sliunted around the contact points of the main make and break point only, substantially as and for the purpose described.

2. In anignition system, a non-back-firing device comprising a source of current and an induction coil for producing sparking impulses; of a duplex make and break device included in the primary circuit of the induction coil, having provisions for operating said duplex devices in quick succession to produce a quick break upon the normal rotation of the engine, but a slow electrical break insuliicient for sparking purposes upon reverse direction of rotation.

3. In an ignition system for intcrnal combustion engines, the combination with a. source of current and an induction coil, of engine controlled means for intermittently interrupting the flow of current to said coil, having provisions for obtaining a breaking of current in the coil at a rate suilicient for sparking purposes upon normal rotation of the engine, and having provisions for obtaining a breaking of current in said coil at too slow a rate for sparking purposes on reverse rotation.

4. In an ignition system for internal-combustion engines, the combination with a source of current and an induction coil, of engine controlled means for intermittently interrupting the flow of current to said coil, said means including a pair of main contacts and a condenser in shunt therewith, and including a pair of auxiliary contacts constructed of a metal which will draw a conducting are when separated to break the ignition circuit, said main contacts opening before the auxiliary contacts during normal engine rotation, but said auxiliary contacts opening before the main contacts upon a reversal of the'engine.

5. In an ignition system for internal-combustion engines, the combination with a source of current and an induction coil, of engine controlled means for intermittently interrupting the flow of current to said coil, said means including a pair of main contacts and a condenser in shunt therewith, and including a pair of auxiliary contacts constructed of nickel whereby to draw a conducting arc when separated to break the ignition circuit, said main contacts opening before the auxiliary contacts during normal engine rotation, but said auxiliary contacts opening before the main contacts upon a reversal of the engine.

In testimony whereof I ailix my signature.

WILLIAM O. KENNINGTON.

Witnesses:

J. W. MCDONALD, M. A. Penna. 

